Inductance coil



Dec. E3? 1927. LGSZ 938 v E. M. HEWLETT INDUCTANCE COI L Filed Sept. 18,1923 5 Sheets-Sheet 1 'UNIF r'u/e VLCOP Edward MH ew Lett,

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3 Sheets-Sheet 2 E. M. HEWLETT INDUCTANCE COIL Filed Sept. 18, 1925 iiil J zo E. M. HEWLETT INDUCTANCE COIL Filed Sept. 18, 1925 3 Sheets-Sheet3 i ma? u N l'- W l W25 f n HN www ll E' Patented Dec. 13, 1927.

UNITED STATES PATENT oFFlcE. l

EDWARD M. HEWLTT, OF SCHENECTADY, NEW YORK, ASSIGNOR T GENERAL .TRIOCOMPANY, (A CORPORATION OF NEWVYORK.

ELEC- INDUCTANGE (10113.l

Application led September 18, 1928. Serial. No. 663,509.

of my invention is to provide an elicient means for spacing andinsulating` from one another the separate turns of the coil.

The novel features which'I believe to be characteristic of my inventionare set forth with particularity in the appended claims.

Theinvention itself, however, both as to its organization and method ofoperation, to-A gether with further objects and advantages thereof willbest be understood by reference to the following description taken inconnection with the accompanying drawing in which Fig. 1 is aperspective-of a coil constructed in accordance with my invention; Fig.2 is a plan view thereof; Fig. 3 is an elevation of a portion of a coilillustrating certain of the structural features thereof; Fig. 4 is adetail showing a modification in the construction of the coil; and Figs.5 and 6 arev perspectives, taken at different angles, of the spacing andinsulating devices. i

As shown in the drawings, vthe coil is built up'around six supportingposts 1 to 6 of insulating material uniformly spaced around thecircumference' of a circle. The lower ends of these posts are providedwith bases 7 which may be secured to any suitable foundation by means ofbolts 8. These posts may comprise porcelain tubes 9 the lower ends ofwhich are surrounded by cylindrical'porcelain insulators 10. The postsare held in their desired'parallel yposition by means of metal bands 11each of which is provided with an insulating joint 12, in order thatthese bands shall not form short circuited secondary windings, for thecoil. The two lower bands 11 are secured to the posts by means ofclamping rods 13 and spacing members 14 of insulating material. Theclamping rods 13 are provided with "insignaling systems sulatingbushings for insulating them from the bands 11 and thus preventing theformation of a closed circuit in which induced currents may flow. In theconstruction of the coil support metal parts are used only wherenecessary to obtain the desired strength as the use of metal parts inthe coil support tends to increase thelosses of the co1 Y The coil whichI have illustrated is of the multl-layer type, each layer consisting offour turns. The turns of the coil are all supported upon,A insulators 15and are all heldin spaced .relation to one another. rlhe insulators 15are of lsubstantially triangular shape having conductor holders in whichretaining grooves 16 are formed secured to two sides thereof. The thirdside of each insulator 1.5 lis provided with a groove 17 for receivingthe porcelain tubes 9. Each insulator is also provided withv an opening18 for receiving a clamping band 19. Each end of the clamping' band 19is attached .to a yoke 20, which surrounds a projection 21 on thespacing block 22. The clamping ff' bands are thereby made discontinuousso that they donot form closed circuits in which induced currents mayflow. The upa per'bands 11 are secured to the posts l1 to 6 by means ofthe rods 23 which are secured i" to the ends of clamping bands 19.

In winding the conductor 24 uponfthe supporting structure, the conductoris first wound upon the inner groove of the top series of insulatorsstarting at point 25 and then' progressively outward until the lastgroove of the top series is reached at 26. The conductor is then carrieddown to the outer groove on the lower side of the next insulator at 27and wound progressively in- @E ward until the last groove on the lowerside of the top series of' insulators is reached. The conductor is thencarried down to the inner'top groove of the next insulator of the secondseries and progressively outward as 100 on the top series. and sol onuntil the end of the coil is reached at the inner groove on the lowerside of one of the insulators of the lowest series.

When the coil is wound in this way it will 105 be noted that.the maximumpotential developed in the coil during operation between the two outerturns of adjacent layers carried by any insulator will be the potentialdeveloped in a single turn of the conductor u@ while the maximumpotential developed bctween the two inner turns of adjacent layerscarried by any insulator will be the potential developed in eight turns.By making the insulators of triangular form the spacing between the twoinner turns carried by each insulator is made enough greater than thespacing' between the two outer turns to take care of the greaterpotential developed between the two inner turns. The distributedcapacity o f thecoil is also reduced by this expedient. Similarly thespacing between the outer turns on the lower side of one series ofinsulators and the top of. the next or adjacent series below is madegreater than the spacing between the inner turns to take care of theincreased potential.

It will also be observed that the conductor retaining grooves on thelower side of the insulators are in staggered relation to the grooves onthe upper side so that the turns of the conductor retained on the lowerside of the insulators are not directly below the turns retained on theupper side of the linsulators. This expedient increases the spacingbetween turns and also reduces the tendency to the formation of partialshort circuits of the turns which might be caused by the formation oficicles between turns due to water dripping from one turn down onto anadjacent turn directly below it.

In the construction of the insulators l5, three important conditions aretaken into consideration; first, a large creepage surface over theinsulator is desirable'between the diierent conductors; second, aportion of this creepage surface should be so arranged that it will atall times remain substantially dry; third, means should be .provided forpreventing the formation of large streams of water which will flow overthe insulator and between adjacent turns of the conductor.

by supporting the conductor holders in which the upper grooves 16 areformed on a central rib 28, which is of less thickness than the lengthof the grooves, and also by the provision of a barrier .29, which isinterposed between the two sets of grooves, and which in turn is widerthan the length of these grooves. A substantially horizontal rib 30 alsoprovides a secondary barrier between the inner grooves of the top andbottom series. Each of thel grooves is also provided with a centralprojection 31 so arranged that the conductor will be in contact onlywith this central projection and will not be in contact with the groovesthroughout their whole length.

The second condition is taken care of byv reason of the fact that theunder portion of the upper set of' conductorholders is not directlyexposed to the elements and the under side of the barrier 29 .is notdirectly The first of these conditions -is providedA exposed. Grooves 32are also referably provided on the lower side of tiie barrier 29, whichprevent water from creeping along 'the lower side of the barrier to thecentral rib 28. The barrier 29 is provided with depressions 33, whichserve to collect water falling on the surface of the insulator and causeit to be broken up into separate streams. The possibility of waterforming in one large stream and running ofi the surface of the insulatorand forming a short circuit between conductors is thereby prevented. Thedepressions are so located that the water dropping from the edge of thebarrier will not fall directly upon the conductors resting in the lowerseries of grooves.

If desired, additional protection may be furnished by means of a barrier34, as shown in Fig. 4, which is interposed between superimposedinsulators. This barrier is provided with a plurality of transversegrooves in order to subdivide as much as possible the stream of waterwhich may iiow over the insulators. n

For convenience in shipment the bands 11 instead of being formed fromone continuous strip of metal may be formed in sections, which arebolted together at points 35, as indicated in Fig. 2.

What I claim as new and desire to 'securel by Letters Patent of theUnited States, is

1; An insulator having a set of conductor retaining grooves formedthereon and arranged in a substantially horizontal plane, and a secondset of grooves formed thereon and arranged in a plane which intersectsthe plane of the first set.

2. An insulator of substantially triangular form having a plurality ofconductor retaining grooves formed on two sides thereon and the thirdside thereof being'adapted to be readilyv attached to a support.

3. .An insulator of substantially triangular form having a plurality ofconductor retaining grooves formed on two sides thereof, the third sideof which is formed to partially embrace a support.

4. An insulator of substantially triangular form having a lurality ofconductor retaining grooves thereof and the grooves in one side beingindividuell out of vertical alignment with correspondlng grooves in theother side.

5. An inductance coil made up of a plurality of layers each layercomprising a plurality of turns,'said turns being all held out ofcontact with one another by a plurality of insulators each of whichsupports at least one turn of two layers.

6. An inductance coil made up of a plurality of layers, each layercomprising a plurality of turns, said turns being all held out ofcontact with one another by a plurality of horizontally mountedinsulators,

ormed on two sides' each of which supports at least one turn of twolayers.

7. An inductance coil made up of a plurality of layers each layercomprising a plurality of turns, said turns being all held out ofcontact with one another by a plurality A of insulators each of whichsupport two layers, the oppositely disposed turns ot each pair ofadjacent layers thus supported heilig spaced at di'erent distances fromone another than any other air.

8. An inductance coll made up ot a plurality of layers, each layercomprising a plurality of turns, said turns being all held out ofcontact with one another by a plurality of insulators which support eachlayer in such a way that the air of turns in adj acent layers betweenwhich the highest potential diiference is developed during operation isseparated b a greater .dista-nce than the other pairs o turns.

9. A multi-layer inductance coil comprising a plurality ofcircumferentially arranged posts, each of which has secured thereto aplurality of spaced supporting insulators, each of which insulatorsserves to support and hold in spaced relation the turns of two layers ofthe coil.

10. An inductance coil comprising a plu-` rality of circumferentiallyarranged posts each of which has secured thereto a plurality ofsupporting insulators of substantiallytriangular form having conductorretaining grooves formed on two sides thereof. 11. An inductance coilcomprising a plurality of circumferentially arranged posts each ofwhich-has secured thereto a plurality of supporting insulators ofsubstantially triangular form having vconductor retaining grooves formedon two sides thereof one of which lies in a substantially horizontalplane.

12. An inductance coil comprising a plurality of circumferentiallyarranged posts each of 'which has secured thereto a plurality ofsupporting insulators of substantially triangular form having conductorretaining grooves formed on two sidesthereof, said grooves servin toretain the individual turns of the coil in spaced relation to oneanother.

13. An inductance coil comprising a plur'ality of circumferentiallyarranged posts each of which has secured thereto a plurality ofsupporting insulators of substantially triangular form having conductorretaining grooves formed on two sides thereofa said grooves serving toretain the indivldual turns of the coil in spaced relation to oneanother, and the turns of the coil being' so arranged that' adjacentturns between'which the highest potential difference is developed duringoperation are separated by a greater distance than other adjacent turns.

14. An insulator of"substantiallytriangular form having a lplurality ofconductor retaining grooves formed ontwo sides thereof, the third sidethereof being ada ted to be readily' attached to a support, an having a'lrctaining r grooves formed on two sides thereof, the third side thereofbeing adapted to be readily attached to a support, and having a barrierinterposed between the grooves on the two sides, said barrier being ofgreater width than the length of the grooves.

17. An insulator having a set of conductor l retaining grooves formedthereon and arranged in a substantially horizontal plane, a second setof grooves formed thereon and arranged in a plane intersecting the planeofthe first set, and a barrier interposed between the two setsof-grooves, sai-d barrier being of greater width than the length of thegrooves.

18. An insulator comprising a central rib, a plurality of conductorholders having conductor retaining grooves secured to opposite edges ofsaid rib and a barrier extending from opposite sides of said rib andinterposed between the conductor holders which are secured to theopposite edges.

19. An insulator comprising a central rib and a plurality of conductorholders having conductor retaining' grooves secured to opposite edges ofsaid "rib, said conductor holders being of materially greater lengththan the thickness of the rib.

20. An insulator comprising a central rib, a plurality of conductorholders having conductor retaining grooves secured vto o posite edges ofsaid rib, said conductor hol ers being of materially greater length thanthe thickness of the rib, and a barrier extendingfrom opposite sides ofsaid rib and interposed between the conductor holders` which are securedto the opposite edges.

' 21. An insulator comprising a central rib, a plurality of conductorholders having conductor retaining grooves secured'to opposite edges ofsaid rib, said conductor holders be'- ing of materially greater lengththan the thickness of the rib, and a barrier extending from oppositesides of said rib andinterposed between the conductor holders which aresecured, to the opposite edges, said barrier being of greater width thanthe length of the conductor| holders.

In witnessr whereof, I have hereunto set my hand this 17th day ofSeptember 1923.

'EDWARD M. HEWLETT.

